What Is Kisspeptin? The Reproductive Hormone Switch

Sexual Health & Intimacy Research

Kisspeptin is the signal that sits at the very top of the reproductive hormone axis: it switches on the GnRH neurons that drive luteinising hormone (LH) and follicle-stimulating hormone (FSH) release. Since 2005, a run of human studies, most of them from Imperial College London, has shown kisspeptin raising LH and testosterone in men, triggering egg maturation in IVF, and changing how the brain processes sexual and emotional cues. Vistara Labs supplies it as a Kisspeptin 10 mg lyophilised vial and a ready-mixed Kisspeptin Nasal Spray.

What is kisspeptin?

Kisspeptin is a family of peptides cut from a single precursor protein encoded by the KISS1 gene. The gene was isolated in 1996 at Pennsylvania State University’s College of Medicine in Hershey, Pennsylvania, the town known for its chocolate kisses, by a team searching for genes that stop melanoma cells from spreading. Its 164-amino-acid protein suppressed metastasis in melanoma cells, and the highest natural expression was in the placenta (Lee et al., J Natl Cancer Inst, 1996).

In 2001, two groups working independently isolated the active peptides from human placenta and matched them to an orphan receptor, GPR54. A Japanese team named the 54-amino-acid product metastin (Ohtaki et al., Nature, 2001), and a Belgian team, which also found 14- and 13-amino-acid forms sharing the same C-terminal end, named the family kisspeptins (Kotani et al., J Biol Chem, 2001). GPR54 was highly expressed in the placenta and pituitary, an early hint of a hormonal role.

Kisspeptin-54 and kisspeptin-10

The numbers refer to chain length. Kisspeptin-54 is the major circulating form in humans (Jayasena et al., J Clin Invest, 2014). Kisspeptin-10 is the last ten amino acids of that chain and is the minimal sequence with full intrinsic activity at the receptor (George et al., J Clin Endocrinol Metab, 2011). Both have been studied in people, and both raise LH.

How kisspeptin controls the reproductive axis

The link to reproduction came from genetics. In 2003, a French group studying a large family with five siblings who had not gone through puberty found that all five carried the same deletion in the GPR54 gene (de Roux et al., PNAS, 2003). A Boston-led group reported the same year that GPR54 mutations cause isolated hypogonadotropic hypogonadism in both people and an animal model, and that the animals still responded normally to GnRH itself (Seminara et al., N Engl J Med, 2003). Without kisspeptin signalling, the GnRH system is never switched on.

The cascade runs in one direction. Kisspeptin neurons in the hypothalamus activate GnRH neurons; GnRH pulses reach the pituitary; the pituitary releases LH and FSH; and those hormones drive the testes or ovaries. Because kisspeptin sits upstream of GnRH, it works through the body’s own pituitary response rather than bypassing it.

What the human studies have shown

LH, FSH and testosterone in men

The first human data came from Imperial College London. In a double-blind, placebo-controlled crossover study, six healthy men received a 90-minute kisspeptin-54 infusion and a saline infusion in random order. Mean LH over 90 minutes rose to 10.8 U/L against 4.2 U/L with saline, and FSH and testosterone also rose significantly. The plasma half-life of kisspeptin-54 was 27.6 minutes (Dhillo et al., J Clin Endocrinol Metab, 2005).

Kisspeptin-10 was tested in men in Edinburgh. A bolus produced a rapid, dose-dependent rise in LH, from 4.1 to 12.4 IU/L at 30 minutes at the most effective level, and a continuous infusion raised testosterone from 16.6 to 24.0 nmol/L. A lower-rate infusion increased LH pulse frequency from 0.7 to 1.0 pulses per hour, direct evidence that kisspeptin speeds the GnRH pulse generator (George et al., 2011).

The menstrual cycle

In healthy women, kisspeptin-54 raised LH in every phase of the menstrual cycle, with by far the largest response in the preovulatory phase, the window just before ovulation, where the mean rise over baseline was 20.64 IU/L (Dhillo et al., J Clin Endocrinol Metab, 2007). That timing fits a role in the LH surge that triggers ovulation.

Triggering egg maturation in IVF

In 53 women undergoing IVF, a single subcutaneous injection of kisspeptin-54 was used in place of the usual trigger to induce the LH surge. Egg maturation occurred at every level tested, fertilisation and embryo transfer took place in 92% of the women, and 12 clinical pregnancies followed (Jayasena et al., J Clin Invest, 2014).

The follow-up focused on women at high risk of ovarian hyperstimulation syndrome (OHSS), a serious complication of IVF. In a Phase 2 randomised trial of 60 such women, oocyte maturation occurred in 95%, the live birth rate per embryo transfer was 45%, and no woman developed moderate, severe or critical OHSS (Abbara et al., J Clin Endocrinol Metab, 2015).

Sexual and emotional brain processing

In 29 healthy young men, kisspeptin enhanced activity in the limbic system specifically in response to sexual and couple-bonding images, the size of that enhancement tracked measures of reward, drive and mood, and kisspeptin reduced negative mood (Comninos et al., J Clin Invest, 2017). A 2020 study found it also strengthened brain responses to smell and visual cues of attraction, most clearly in men with lower sexual quality-of-life scores (Yang et al., JCI Insight, 2020).

Two randomised, double-blind, placebo-controlled crossover trials followed in people with hypoactive sexual desire disorder (HSDD). In 32 premenopausal women, kisspeptin modulated brain processing of erotic videos and attractive faces, and was well tolerated with no reported adverse effects (Thurston et al., JAMA Netw Open, 2022). In 32 men, it modulated activity across the brain’s sexual-processing network, increased penile tumescence in response to sexual stimuli by up to 56% more than placebo, and increased reported happiness about sex (Mills et al., JAMA Netw Open, 2023).

Kisspeptin-10 and kisspeptin-54 at a glance

Question	Kisspeptin-10	Kisspeptin-54
Length	10 amino acids	54 amino acids
Relationship	Minimal active C-terminal sequence	Major circulating form in humans
Key human finding	Raised LH and LH pulse frequency in men (2011)	Raised LH in men and women; triggered IVF egg maturation (2005 to 2015)
Brain imaging research	Not the focus of the main trials	Used in the 2017 to 2023 sexual-processing trials

How kisspeptin compares with other compounds

Kisspeptin works upstream of the pituitary, which separates it from HCG, which acts on the gonads directly (Kisspeptin vs HCG), and from enclomiphene, which raises LH by a different route (Kisspeptin vs Enclomiphene). Its bonding and desire research invites comparison with oxytocin and PT-141.

How Vistara Labs supplies kisspeptin

Kisspeptin comes as a 10 mg lyophilised vial, reconstituted with bacteriostatic water (the concentration arithmetic is in how much bacteriostatic water for a kisspeptin 10 mg vial), and as a ready-mixed metered nasal spray at 0.175 mL per press, which needs no mixing. Certificates of analysis are on the lab reports page, and the buying questions are answered in Buy Kisspeptin in Canada.

Frequently asked questions

What is kisspeptin?

Kisspeptin is a family of peptides encoded by the KISS1 gene that activate the receptor KISS1R (GPR54). Kisspeptin neurons switch on the GnRH neurons that drive LH and FSH release, which places kisspeptin at the top of the reproductive hormone axis.

What is the difference between kisspeptin-10 and kisspeptin-54?

Kisspeptin-54 is the full 54-amino-acid peptide and the major circulating form in humans. Kisspeptin-10 is its last ten amino acids, the minimal sequence with full activity at the receptor. Both raised LH in human studies.

What has kisspeptin research shown in humans?

Kisspeptin-54 raised LH, FSH and testosterone in healthy men (2005), raised LH most strongly before ovulation in women (2007), and triggered egg maturation in IVF, with maturation in 95% of 60 women at high risk of ovarian hyperstimulation syndrome (2015).

What has kisspeptin brain research shown?

In placebo-controlled imaging studies from Imperial College London, kisspeptin enhanced limbic brain responses to sexual and bonding cues in 29 healthy men (2017), and modulated sexual brain processing in women (2022) and men (2023) with low sexual desire, with increased penile tumescence and happiness about sex in the men’s trial.

Where can I buy kisspeptin in Canada?

Vistara Labs supplies kisspeptin as a 10 mg lyophilised vial and a ready-mixed nasal spray for research use, shipped from within Canada by Canada Post Xpresspost.

Product details from vistaralabs.ca, October 2026. Sources: Lee JH et al. KiSS-1, a novel human malignant melanoma metastasis-suppressor gene. J Natl Cancer Inst. 1996. PMID 8944003. Ohtaki T et al. Metastasis suppressor gene KiSS-1 encodes peptide ligand of a G-protein-coupled receptor. Nature. 2001. PMID 11385580. Kotani M et al. The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54. J Biol Chem. 2001. PMID 11457843. de Roux N et al. Hypogonadotropic hypogonadism due to loss of function of the KiSS1-derived peptide receptor GPR54. Proc Natl Acad Sci U S A. 2003. PMID 12944565. Seminara SB et al. The GPR54 gene as a regulator of puberty. N Engl J Med. 2003. PMID 14573733. Dhillo WS et al. Kisspeptin-54 stimulates the hypothalamic-pituitary gonadal axis in human males. J Clin Endocrinol Metab. 2005. PMID 16174713. Dhillo WS et al. Kisspeptin-54 stimulates gonadotropin release most potently during the preovulatory phase of the menstrual cycle in women. J Clin Endocrinol Metab. 2007. PMID 17635940. George JT et al. Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men. J Clin Endocrinol Metab. 2011. PMID 21632807. Jayasena CN et al. Kisspeptin-54 triggers egg maturation in women undergoing in vitro fertilization. J Clin Invest. 2014. PMID 25036713. Abbara A et al. Efficacy of kisspeptin-54 to trigger oocyte maturation in women at high risk of ovarian hyperstimulation syndrome (OHSS) during in vitro fertilization (IVF) therapy. J Clin Endocrinol Metab. 2015. PMID 26192876. Comninos AN et al. Kisspeptin modulates sexual and emotional brain processing in humans. J Clin Invest. 2017. PMID 28112678. Yang L et al. Kisspeptin enhances brain responses to olfactory and visual cues of attraction in men. JCI Insight. 2020. PMID 32051344. Thurston L et al. Effects of kisspeptin administration in women with hypoactive sexual desire disorder: a randomized clinical trial. JAMA Netw Open. 2022. PMID 36287566. Mills EG et al. Effects of kisspeptin on sexual brain processing and penile tumescence in men with hypoactive sexual desire disorder: a randomized clinical trial. JAMA Netw Open. 2023. PMID 36735255.

More on this: Peptides for Libido: What the Research Shows.